Ultrafast dynamics in the presence of antiferromagnetic correlations in electron doped cuprate La2 xCexCuO4±δ Journal Article


Author(s): Vishik, Inna M; Mahmood, Fahad; Alpichshev, Zhanybek; Gedik, Nuh; Higgins, Joshu S; Greene, Richard L
Article Title: Ultrafast dynamics in the presence of antiferromagnetic correlations in electron doped cuprate La2 xCexCuO4±δ
Affiliation
Abstract: We used femtosecond optical pump-probe spectroscopy to study the photoinduced change in reflectivity of thin films of the electron-doped cuprate La2-xCexCuO4 (LCCO) with dopings of x=0.08 (underdoped) and x=0.11 (optimally doped). Above Tc, we observe fluence-dependent relaxation rates that begin at a temperature similar to the one where transport measurements first show signatures of antiferromagnetic correlations. Upon suppressing superconductivity with a magnetic field, it is found that the fluence and temperature dependence of relaxation rates are consistent with bimolecular recombination of electrons and holes across a gap (2ΔAF) originating from antiferromagnetic correlations which comprise the pseudogap in electron-doped cuprates. This can be used to learn about coupling between electrons and high-energy (ω>2ΔAF) excitations in these compounds and set limits on the time scales on which antiferromagnetic correlations are static.
Journal Title: Physical Review B
Volume: 95
Issue 11
ISSN: 24699950
Publisher: American Physical Society  
Date Published: 2017-03-13
Start Page: Article number: 115125
Sponsor: Optical pump-probe work was supported by the Gordon and Betty Moore Foundation's EPiQS initiative through Grant No. GBMF4540. Materials growth and characterization was supported by AFOSR FA95501410332 and NSF DMR1410665.
URL:
DOI: 10.1103/PhysRevB.95.115125
Open access: yes (repository)